Duloxetine As an Analgesic in Patients Without Central Sensitivity After Same Sitting Bilateral Total Knee Arthroplasty

Inclusion Criteria: * Bilateral tricompartmental knee osteoarthritis * Underwent primary, bilateral TKA in single-sitting Exclusion Criteria: * American Society of Anesthesiologists physical status IV * Hamilton Depression Scale (HAMD) and/or Hamilton Anxiety Scale (HAMA) scores \> 7 * known intolerance or allergy to any of the study drugs, alcohol, tobacco, narcotic, or opioid dependence * patients on anticoagulants * known hepatic/renal dysfunction * serious cardiac/cerebrovascular comorbidities * HbA1c≥7 * patients who were already on duloxetine or other SNRIs, monoamine oxidase inhibitors, tricyclic antidepressants, triptans, lithium, other antiepileptics, or buspirone.